Stabilizer migration

When a polymeric system is exposed to high-energy radiation, the system undergoes main-chain scission and the creation of cross-links, end-links, double bonds, free radicals, etc. The neutral radicals are the key promoters of the reactions above, and the structure, reactivity (stability), migration, etc., have been extensively investigated by many techniques including ESR. Details of the techniques and their results are described in other chapters or reviews (for a book, see Ref. 29), and the eifects of the above reactions on polymeric systems are mainly discussed in the present section. 

Isoindolinones and Isoindolines. Tetracliloroisoindolinone pigments are characterized by very good lightfastness, heat stability, migration resistance, and chemical inertness. Although Pigment Yellow 110, a red-shade yellow, is relatively weak, it finds extensive use in automotive and... 

Silicones Highest purity. Stress absorbing. High and low temp, stability. Migrate to other circuit elements. Low surface energy. Swelled by nonpolar solvents. 

Uses Plasticizer for PVC and rubber formulations such as wire and cable coatings offering good elec, props., film, tape, and coated fabrics Features Good humidity stability, migration resist, to rubber, oil and hexane resist., low volatility Properties Low odor med. m.w. 

Uses Stabilizer migrating from food pkg. Regulatory FDA 21CFR 181.29 Manuf./Distrib. Aerchem http //www.aerchem.com Ashland http //www.ashchem.com Vopak USA http //WWW. vopakusa. com Ammonium citrate dibasic CAS 3012-65-5 EINECS/ELINCS 221-146-3 UN 9087 INS380... 

Ammonium potassium hydrogen phosphate Hazardous Decomp. Prods. Heated to decomp., emits acrid smoke and irritating fumes Uses Stabilizer migrating from food pkg. in food-pkg. adhesives Regulatory FDA 21CFR 175.105, 181.29 Ammonium propionate CAS 17496-08-1 El NECS/ELINCS 241-503-7 Synonyms Propanoic acid, ammonium salt... 

Toxicoiogy Skin and eye irritant nuisance dust Uses Pharmaceuticals (tablet diluent) stabilizer migrating from food pkg. in resinous/polymeric food-contact coatings... 

Uses Foods (dietary supplement, mineral supplement) pharmaceuticals (tablet diluent excipient abrasive in dentifrices calcium/phosphorus source in multivitamins) stabilizer migrating from food pkg. 

Hazardous Decomp. Prods. Heated to decomp., emits acrid smoke and irritating fumes Uses Stabilizer migrating from food pkg. 

It has been found that the fate and transport of colloids and colloid-associated contaminants in saturated porous media are controlled by a combination of several basic factors including (1) the presence of colloidal particles in the subsurface environment (2) their release, dispersion stability, migration, and straining/plugging at pore constrictions and (3) association of contaminants with colloidal particles/solid matrix (Sen and Khilar, 2006,2009 Sen et al., 2002,2004,2005). Similar observations by several investigators have been compiled by Sen and Khilar (2009). 

Stabilizer migration resistance tested in accordance with 7.10 ASTM F 876. 

Of special consideration are systems with symmetry where both separatrix loops approach together the saddle point. Such a situation is rather trivial namely when the loops split inwards, each gives the birth to a single stable limit cycle, in view of Theorem 13.4.1. When the loops split outwards, the stability migrates to a large-amplitude symmetric stable periodic orbit that bifurcates from the homoclinic-8 as shown in Fig. 13.7.2. And that is it. This is the reason why the theory below focuses primarily on non-symmetric systems. 

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